<!DOCTYPE html>
<html lang="en" xmlns:v-on="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="vue.js"></script>
</head>
<body>
<div id="app">
    <button v-on:click="count++">add</button>
    <p>{{count}}</p>
</div>

<script>
var app = new Vue({
    el: "#app",
    data: {
        count: 0
    }
})


</script>


</body>
</html>